There has been some confusion about what constitutes natural, or bio-identical, hormones so let’s start by looking at the role of those hormones.
What are hormones?
The Ovaries act as endocrine glands when they produce the oestrogens and progesterone that control a woman’s menstrual cycle and fertility. They make some very important hormones and amongst these are three oestrogens, as well as progesterone. These hormones then pass into the blood stream where they are transported to wherever they are needed in the body.
The ovaries produce the three oestrogens: Oestradiol, Oestrone and Oestriol. These are secreted in different amounts and ratios to each other at different stages in a woman’s life.
Oestradiol is the strongest and is produced in large amounts by the ovaries during a woman’s reproductive years.
Oestriol is a gentle oestrogen produced in large quantities by the placenta during pregnancy and also in larger quantities after the menopause.
Oestrone is also produced in greater amounts after the menopause and it too is also a gentler oestrogen than oestradiol.
Sometimes the total amount of oestrogens produced after the menopause can be as high as before the menopause. This can then produce a situation of oestrogen dominance because ovulation has ceased and the amount of progesterone being produced has dropped considerably. This may need to be corrected with progesterone supplementation.
Progesterone is produced throughout the monthly cycle, but the amount increases at ovulation as one of its important roles is to prepare the body for pregnancy. Progesterone is also very important in that it protects the body against the unwanted effects of the oestrogens. These include:
increase in stimulation of the lining of the uterus
stimulation of breast tissue
There are times when the body’s hormones are out of balance and additional amounts may be given. There are two types that are available:
1. Natural, or bio-identical, hormones which are molecularly identical to those made by the body.
2. Synthetic, or chemical, hormones and, although these have similar actions to our own body’s natural hormones, they also have additional and often unwanted and potential dangerous actions. This is because their molecular structure is different from the body’s natural hormones; that is to say that they are not identical to those made by the body.
This is usually prescribed to contain oestradiol combined with a chemical progestogen (not progesterone as made by the ovary) in a standard dose.
The progestogen is put into the mixture for one reason only: to protect the uterus from over stimulation by the oestradiol. This over stimulation if not controlled can lead to cancer of the uterus. The reason a chemical progestogen is used rather than the bio-identical progesterone is because natural progesterone cannot be patented, but the chemical form can.
Sadly, the artificial progestogen does not protect the body from any of the other unwanted effects of oestrogens either. In addition it is now realised that these progestogens can in fact increase the risk of over stimulation of the breasts by oestrogen.
In recent surveys it has been found that women who take oestradiol combined with progestogens (normal HRT) have a slightly higher risk of breast cancer than women who only take oestradiol.
Oestradiol on its own is usually only prescribed to women who have had a hysterectomy.
When bio-identical HRT is prescribed it is usual for a combination of the three naturally occurring oestrogens combined with progesterone to be used. This means that the body is receiving as near as possible the combination of hormones that the ovaries themselves produced. Also the progesterone protects the body against all the unwanted effects of oestrogens, not just the uterus. This means that the increased risk of breast cancer that exists when taking additional oestrogens should be considerably less than when taking traditional HRT.
The dosage of these oestrogens and progesterone is individually adjusted to the individual woman and based upon her response to them, not given as a standard dose.
The dosage can be adjusted by reference to a blood or saliva test but this is not as reliable a way as simply adjusting the dosage to the woman’s response to the hormones.
The reason for this is that the results of both blood tests and saliva testing of hormones will vary from day to day and the actual hormone blood level required by one woman will not be the same as another.
Sometimes instead of prescribing all three oestrogens the doctor may just prescribe the weak oestriol, or oestriol and oestrone combined with progesterone.
How Is It Given?
The three bio-identical oestrogens are given as a tablet (Hormonin) and Oestradiol can be prescribed as a vaginal cream or pessary or as a tablet (Ovestin).
The Progesterone can be prescribed as a transdermal cream (such as Wellsprings Serenity), a tablet (Uterogestan) or as suppositories (Cyclogest).